It seems that way, yes
Indeed.
And as we know, finishing positions have nothing to do with matches.
Lines seem blurry to me.
It's like saying in cricket it's ok to bet on a test series but not an individual test match. Either way the player is conflicted with a specific match when it gets to the last test. Same case applies in football. Wilshere's bet on finishing above Tottenham went down to the last day - making it dependent on a specific match.
It's obviously for fun. They earn enough to not give a fuck about making/losing £100 here or there. But if you're going to be petty enough to discipline for specific matches, a group of matches (which a league season or a cup campaign is) has to be counted the same for consistency.